JPS61295581A - Multi-color image forming device - Google Patents

Abstract

PURPOSE:To shorten an image formation time by selecting >=2 moving speeds for a transfer body. CONSTITUTION:When an image of a specific color is formed on a drum 1, one of developing devices 131, 132, 133, and 134 corresponding to the color comes close to the drum 1 to form an image and when an image of a different color is formed, they rotate as shown by an arrow 135 and a developing device of the desired color is put close to the drum 1. A recording material 14 in a cassette 15 is sent out of the cassette 15 and passes between a couple of register rollers 17 and 18 to be sent to a paper feed guide 19, so that the front end is caught by a gripper 201 on a transfer drum 20 while timed by the rollers 17 and 18. Then, the transfer paper 14 passes between an electrostatic attracting charger 23 and a squeezing roller 22 and is attached to and held on an attraction sheet 202 on the drum 20 to transfer an image from the drum 1. The transfer drum and photosensitive drum rotates at the same speed V1 and then rotated at a speed V2 faster than the V1 for a specific time after the transfer operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to an apparatus for recording a multicolor image, particularly a multicolor image forming apparatus such as a multicolor or full-color printer, and sometimes corresponds to color components. The present invention relates to a multicolor image recording apparatus that includes a transfer member that multiplexly transfers images of each color sequentially formed on an image carrier onto a recording material based on good image information.

[5@Bright background] In order to create a multicolor image, the original image is color separated into yellow (hereinafter abbreviated as Y), magenta (hereinafter abbreviated as M), cyan (hereinafter abbreviated as M), and cyan (hereinafter abbreviated as M). , C) and black (hereinafter, abbreviated as Bk) may be formed in a multiplex manner on a single recording material. As such a multicolor image recording device, the recording material is held by a member with any force ≧,
4. Forming images of each color and transferring them multiple times onto the recording material 4
It has been considered and put into practical use.

Typically, a plurality of image forming drums are arranged on a moving recording material holder, and images are formed by each image forming drum as the recording material moves, and these images are combined into one sheet. Transferring it onto a recording material to obtain a force 2-image (hereinafter 4-
A multicolor image is created by forming images of each color on one image drum in different order, and then reciprocating or rotating the recording material accordingly to transfer the images of each color sequentially onto the recording material. (hereinafter referred to as 1-drum type). Let's talk about the characteristics of each.First, there are 4-
As for the drum type, a multicolor image can be obtained according to the movement of the recording material, so the printing speed can be fast. However, although there is a time for the recording material to pass between the image forming drums of each color, the image forming operations must be started at exactly the same time. Therefore, the image information is stored in one W and is transferred to the image forming drums of each color via side legs. Furthermore, since a multicolor image is formed, the image information is equal to the number of separated colors, that is, three or four times as many as that of a black and white image, and the recording itself involves rotation.

Next, in the case of the 1-drum type and the 2-drum type, the recording material performs reciprocating or rotational movement, so the printing speed 7f is lower than in the case of the 4-drum type. However, since image formation for each color can be performed according to the movement of the recording material, it is relatively easy to form multiple images by linking the separated color image information to the recording material. A color image is obtained.

For the above reasons, the one-drum format is now overwhelmingly in practical use among multicolor image recording devices, although it is inferior in terms of printing speed.

Here, we will explain the 1-drum type in more detail. 1 Normally, the recording material is rotated at a constant rate while being held by a drum-shaped member, and depending on the number of rotations, images are formed in accordance with the color separation, and a multicolor image is obtained on the recording material. . In other words, the printing speed is determined by the rotation of the recording material holder or by the 1-i circulation time. Therefore, printing speed can be improved by reducing the number of rotations or the rotation time.

Regarding the image formation time, when applying Iseiko photography, the image forming speed is naturally determined from issues such as the band 4 characteristics of the photosensitivity and the development characteristics, and then,
The rotation time of the recording medium holding member is also determined. The same applies to other image forming operations such as inkjet and thermal transfer. Next, consider the rotation speed.

4) While the recording material holding member moves one round in contact with the photosensitive drum, image formation for -color is completed, so Y, M, C
, Bk, the recording material holder needs to rotate as much as 4 near the edges. Considering the length of the recording material on the recording material holding member, the circumference of the recording material holding member is 81Il! The hardness is comparable to the maximum hardness of the recording material used in the Li image forming apparatus. This is to reduce the image forming time as much as possible when the largest recording material is used. Therefore, when the largest recording material is held by the recording material holding member, there is only a small portion of the recording material holding member where no recording material is placed.

However, when recording materials other than the largest recording material are held (
For example, if the recording material holding member is half the size of the largest one), approximately half of the periphery of the recording material holding member will be in a state where no recording material is placed on it. Moreover, even though no image is formed when this portion comes into contact with the photosensitive drum, it moves at the same speed as when forming an image. In other words, in the conventional apparatus, when a recording material other than the largest recording material was used, the time required was shorter than necessary.

(Objective of the Present Invention) The object of the present invention is to form a 1-drum type multicolor image in which each color image is formed by sequentially receiving color separation information of at least two images. The purpose of this invention is to prevent the reduction in image forming time that has occurred and to achieve a competitive image forming time on recording materials of all sizes.

(Summary of the Invention) The multicolor image forming apparatus t of the present invention sequentially obtains information corresponding to the color components of at least two or more images by an image means, and sequentially forms each color image by moving four times. , in a multicolor image forming apparatus equipped with a transfer body that transfers images onto a recording material in multiple ways, the transfer body can select two or more moving speeds, and the transfer body is configured to transfer images based on color component information. Forms a color image on the transfer material together with the image forming means, moves at a first movement speed when transferring the color image onto the recording material on the transfer body, obtains color component information, and obtains next color component information. Until then, it moves at a second movement speed that is faster than the first movement speed (
It is something to do.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 shows a multicolor image recording apparatus (hereinafter referred to as a printer) to which the present invention is applied, which uses an electrophotographic method.

In the figure, it has the shape of a photosensitive drum constituting a single image carrier, and is rotating in the direction of arrow 2. A charger 12 , a developer group 13 , a transfer drum 20 , and a cleaner 27 are arranged around the photosensitive drum 1 . 10 and 11
is a laser optical system that separates the colors and forms an image on the drum 1 from the next image. 10 is a polygon mirror,
11 is a laser reflecting mirror. The developer group 1S is Y, JC!, respectively. , Bk developer.

When forming an image of a specific color on the drum 1, the developer 131, 132, 133 or 154 of that color forms the image adjacent to the drum 1, and when forming an image of a different color. rotates in the direction of arrow 135 to bring the desired color of the drawer adjacent to drum 1.

Reference numeral 15 denotes a cassette that stores the recording material 14 (normally plain paper is used). The recording material 14 (hereinafter referred to as transfer paper) in the cassette 15 is sent out from the cassette 15 by a paper feed roller 16, passes through a second registration roller 17 and a second registration roller pair 18, and is sent to a paper feed guide 19. The transferred paper is timed by the heat removal 1 and second registration rollers 17 and 1B during passing, and the tip is held by the gripper 201 on the transfer drum 20.The gripped transfer paper is transferred to an adsorption charger. 23, it passes between the squeezing rollers 22 and is carefully sucked and held by the suction sheet 202 on the transfer drum 20 over the entire area. The attracted transfer paper is transferred to a transfer charger 24, and the image on the drum 1 is transferred thereto. Transfer 1 is repeated for each color, and when the transfer is completed, the gripper opens and the separation claw 28 guides the transfer section 29. The electrostatic transfer paper is guided to the conveying section 29, passes through a pair of fixing rollers 30 and 51, is fixed, and is placed on a tray 52. The image remaining on the drum 1 after the transfer process is cleaned by a cleaner 27, and the drum is prepared for the next image formation.

Note that 25 and 21 are cams that open and close the gripper on the transfer drum.

FIG. 3 is a diagram showing the relationship between the photosensitive drum 1 and the transfer drum 20. A photosensitive drum gear 10 is provided at the end of the photosensitive drum 1.
1 is engaged with the transfer gear of the transfer drum 20. Therefore, the surfaces of the photosensitive drum 1 and the transfer drum 20 rotate at the same speed. Photosensitive drum gear 1o1t
The driving force from the i-motor 37 is received by the driving gear 34 via the timing belt 38 and timing belts 49 and 40, and is driven by the driving gear 34.

In the middle of this drive system, a reference pulse generation section consisting of a pulse plate 35 and a pulse signal generation element 36 is provided, and each part of the printer is activated by the pulses generated by this reference pulse generation section. 20
Inside, there is a transfer charger 24 for transferring the image on the photosensitive drum to transfer paper, a gripper cam 25 for opening and closing the gripper 201, and at least three cams on the circumference of the transfer drum.
There are a support shaft 205 and a support shaft 204 that support the device at several locations.

A suction sheet 202 for suctioning the transfer paper onto the transfer drum is attached to the transfer drum 20. Such speed control means is provided on the outer end surface of the transfer drum 20 at a position corresponding to the gripper 201. ratio 20
6, and a mental sensor 33 provided on the main body of the device to detect the claw 206.

The reason why the claw 206 is in the gripper position is because the transfer paper is held in its grip by the gripper, so the claw position becomes the leading edge of the transfer paper and the leading edge of the pick image, and by detecting the position of the claw, it is easy to control the timing of image formation and drawing. It is from b.

The sensor 33 is located away from the transfer position on the circumference of the transfer drum by a distance equal to the distance from the laser writing position on the circumference of the photosensitive drum to the transfer position [20A]. Therefore, the gripper signal generated when the sensor 35 detects the gripper is scanned and written using the optical laser.

Figure 4 shows the relationship just described.

FIG. 1 shows the time, speed of the photosensitive drum and transfer drum, gripper control signals, image writing, development operation, transfer operation, and control pulses when the control according to the present invention is performed. A case where the above control is applied to the apparatus shown in FIG. 1 will be explained. First, the transfer drum and photosensitive drum have the same speed (V
, ) is moving. At the same time as the gripper signal is detected, an image is written using a laser, and development and transfer are activated after a certain period of delay. Note that the means for measuring a certain period of time is possible by counting the number of pulses in the conventional manner. When the transfer is completed, the transfer drum and photosensitive drum move at a speed V! higher than vl. This operation is performed for YMO and Bk.

Here, the time from one gripper signal to the next gripper signal is t0, and the time from gripper signal to the end of transfer is t. 1,
Letting to- be the time from the end of transfer to the gripper signal, to = to+ + teffi-(1).

The time (To) required for image formation is calculated from the first gripper signal as follows: T0=s x t0+ to+ -(2).

Next, Figure 8g5 shows the state of each part when the conventional speed is kept constant. The basic operating procedure of each part is the same as in the case of FIG. Here, the time from the gripper signal to the gripper signal is t8, the time from the gripper signal to the end of transfer is tits, and the time from the end of transfer to the gripper signal is tI! Then, t, =t,, +t,, -(a).

The time ('r+) used for image formation is calculated from the first gripper signal and becomes TI=5 t+ + tn-(41).

However, since the speed v1 is the same from the writing of the image to the end of the transfer, t++ = t'n+ (51, therefore T,
, T, can be expressed by the following formula.

T0=4・to, + 5・to! (6) Tt=4t,
,+3t,! -(7) Here t. ! Since there is a difference between the number of stations and V at +t12 (for example, if vf=2V), t1=] and T, == 4t0. +6・tow (8)
It can be expressed as

The difference between To and TtO is 5 tat, which proves that the present invention reduces the conventional image forming time.

In the description of the above embodiment, a rotary developing device was used as the developing means for the photosensitive drum, but the present invention is not limited to this, and a plurality of developing devices for each color may be arranged around the photosensitive drum. However, it goes without saying that the same effect can be obtained.In the above explanation, the present invention was implemented and explained in relation to an electrophotographic recording device having a photosensitive drum, but the present invention can be applied to other image forming devices. It can also be applied to means, side lighting, inkjet, thermal transfer, etc. Such an embodiment is shown in FIG.

FIG. 6 shows a device that wraps a transfer paper 62 around a transfer drum 61 and outputs a white color image using a circular head 63 serving as an image forming means. The length of the ink ribbon 64 for one color is fr? Y, M, O, and Bk inks having at least the same length as υ are successively formed into a sheet in order and are fed in the moving direction of the transfer drum 61 at the same speed as the transfer drum during image formation. In this case, the overall image forming time can be shortened by increasing the feeding speed of the transfer drum and ink ribbon when the image formation of a certain color is completed and the next image formation is to be performed.

(Effects of the Invention) As described above, according to the present invention, the conventional image forming time can be shortened, and thereby the number of prints per unit time can be increased.

[Brief explanation of the drawing]

Figure 1 is a time chart diagram of an image forming apparatus based on the present invention, Figure 2 is a sectional view of a color recording apparatus to which the present invention is applied;
FIG. 3 is a perspective view showing a photosensitive drum as an image carrier and a transfer drum as a transfer body, FIG. This figure shows a conventional time chart for comparison with FIG. 1, and FIG. 6 shows a sectional view of a recording apparatus according to another embodiment of the present invention. In the figure, 1 is the photosensitive drum, 15 is the current instrument, 14.6
2 is a transfer paper, 20.61 is a transfer drum, and 33 is a sensor.

Claims (1)

[Claims] (1) A transfer body is provided which sequentially obtains information corresponding to the color components of at least two images by an image forming means, moves endlessly to sequentially form each color image, and transfers the images to a recording material in a multiplex manner. In the multicolor image recording device, the transfer body is capable of selecting two or more moving speeds, and the transfer body forms a color image on the transfer material together with an image forming means based on the color component information, and transfers the image. The body moves at a first movement speed when transferring a color image onto a recording material, and moves at a second movement speed faster than the first movement speed between obtaining color component information and obtaining the next color component information. A multicolor image forming device that is characterized by being moved by.